1. Field of Invention
The invention relates to pliers and more particularly to ratchet pliers for either internal type or external type of snap ring.
2. Description of Related Art
Snap rings (or called retaining rings) are shaped as C and are either “internal” or “external”. The internal type of snap ring is used to retain elements (e.g., bearings or shafts) within a bore. In order to install the ring it is contracted to allow it to pass into the bore, and then allowed to expand for engagement with an internal groove formed around the bore. The external type of snap ring is used to retain elements (e.g., bearings, gears or pulleys) on shafts. An external snap ring normally engages an annular groove formed in a shaft to inhibit axial movement of an element mounted on the shaft. An external snap ring is installed by expanding the ring until its internal diameter is greater than the shaft diameter. The tools used for installing and removing internal and external snap rings are well known in the art.
For example, there are types of snap ring pliers specifically for either an internal snap ring or an external snap ring. There is also a type of universal snap ring pliers which are adapted to manipulate either an internal snap ring or an external snap ring. There is another type of snap ring pliers having adjustable jaws.
There is one drawback common to all of above typical snap ring pliers. In detail, the installation or removal of a snap ring requires an individual to hold the snap ring firmly by holding the snap ring pliers with the hand. An unintentional loosening of the holding due to carelessness or sudden exhaustion prior to finishing the work may cause the snap ring to fall. To the worse, the stored elastic energy of the flexibly deformed snap ring may cause the snap ring to fly, hit and hurt the individual who holds the snap ring pliers. This is unsafe. The reason for the drawback is that there is no mechanism (e.g., ratchet) provided by the snap ring pliers for step-by-step or precisely maintaining the relative position of the pliers and the snap ring in the holding operation. Thus, the need for improvement still exists.